DIY Window down, Slight problem

I'm installing a one-touch keyless window system as an add-on to an alarm I recently installed in my 1995 Toyota Corolla. Yes, it's a DIYer using relays--shame on me--but no, I'm not getting fancy with it. The unit simply rolls down the left-rear window when I press the 'trunk' button on my alarm's keyfob. One window, one direction: DOWN. I just want to be able to throw my crap in the backseat because my trunk-pop is not electrical.

For some background, here's my setup:


1. Crappy alarm that gets the job done :)
2. Trunk wire from alarm that pulses when 'trunk' on keyfob is pressed.
--From here on all my +12v lines run through a 20A fused wire--
3. Trunk wire activates DEI528T Pulse Timer Relay set for appx. 3.5 seconds (the time it takes for my window to roll down). This timing is perfect.
4. DEI528T Activates two Bosch 30A Automotive relays. One relay provides +12V to the appropriate wire on the window motor itself while the other provides the negative.. all for appx. 3.5 seconds as specified above.
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-All four windows can be controlled in the car using the driver's control module in the driver's door.
-Each window has its own control.
-Driver's control has a passenger-window-lock button.
-The driver's window has an auto-down function.
-The motor legs on my window are grounded at rest.
-Power to the windows is cut when the car is not in ACC/ON.
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And you know what? My setup works perfectly fine.

With one caveat: The switch for this window must be pressed down for the operation to complete efficiently.

If I use an unfused +12V/- on the window motor directly--without pressing the button down--the window moves VERY slowly, the wires I connected begin to heat and eventually will produce smoke. I didn't take it beyond that. :P

Take the same situation as above and add a 20A fuse on the +12V--still no down-button--and the fuse pops.

And yet, with key out and a simple +12V/- run to the motor wires, if I press the switch for that window down, it rolls down as if the car were on.

I installed my relays as-is, because it works, it's just a bit of a hassle. And I think it can be fixed.

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SO, How might I remedy this situation? I don't want to have to wedge my left-rear window switch into the down position every time I leave the car.

I'm no electrician--not even close--but my best guess is that the window control module is attempting to sink all the juice I throw at the left-rear motor, and I need to put some diodes in, or use a couple more relays to isolate the motor while it is being run by my timer, or something. I don't know.

Sorry for the long post. Thanks.

well that post really confused me but from what was said and understood is that your wires are not big enough to take the load of the motor, so if im right and understood, which i dont think i did, then just get a bigger  gauge wire for the motor

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Okay, put simply, the wires work just fine, it's just that the car is making me actually push the window switch in order to make it work, even when I've got the window motor hooked straight up to the battery.

If I just hook up the wires without pressing my window button down, the wires get hot, etc..

It's gonna be pretty hard for me to press the button from outside the car, and I don't want to have to use something to hold the button down.

Basically, with the current setup, if I want to open that window by pressing the trunk-pop switch on my keyfob, something has to be physically holding the window switch down on the inside of the car. That sucks.

You should only need one relay, but you also must interrupt (cut) one of the wires on the Toyota; have you done that?

It should as simple as this:

1. Test the two wires at the window motor.

They will already both rest at ground when the window is not being used.

One wire will change to positve when raising the window; the other will change to positive when lowering.

2. Take the window-down wire, and cut it in half.

Wire your single relay like this:

85, 87: fused 12 volts constant

86: negative window-down output from 528T timer

87a: Toyota window-down wire; switch-side

30: Toyota window-down wire; motor-side

That should do it.

You make too much sense, Chris Luongo.

Your description does sound like it should work. I've been trying to think up that same thing but I've been up for a few days and the thoughts aren't exactly flowing..

One thing though: I think the wires rest open when the car is off. Therefore, shouldn't I use my other relay to connect the opposite motor wire to ground?

Or maybe the car's window wiring relay will take care of that. I'll start working and see how things go down.

Thanks for your help! :)

Chris Luongo, the leads are actually grounded whether the car is on or off, as was originally assumed.

Your solution did the trick. *tips hat*

Thank you very much. Thread over; solution found. :)